1. Field of the Invention
The present invention relates to a composite cable used for transmitting electric signals from an ultrasonic probe etc. More specifically, the present invention relates to a composite cable having a refrigerant pipe, and a composite cable processed product using such a composite cable.
2. Description of the Related Art
An inspection device using an ultrasonic wave is utilized, for example, in a tomographic inspection in a medical field or in a defect inspection of various structural objects. Such inspection devices that use ultrasonic waves conduct a kind of image inspection method in which an internal state of a target object is inspected in a nondisruptive manner by applying ultrasonic waves to the target object and converting the reflected ultrasonic waves into images. Especially in the medical field, since it is possible to observe a motion of each soft tissue in real time without a radiation exposure, such inspection devices are frequently used.
Such a medical inspection method using ultrasonic waves is an inspection method in which an ultrasonic probe having a piezoelectric vibrator is applied to a human body, ultrasonic waves are irradiated, and the ultrasonic reflected waves are received. The piezoelectric vibrator is disposed inside a tip portion of the ultrasonic probe where a human body is to be applied. A transmitting and receiving circuit is also disposed in the vicinity of the tip portion of the ultrasonic probe so as not to be affected by noises. Therefore, a temperature of a portion where the piezoelectric vibrator is disposed may become high, whereby a patient may suffer from burns or an operator may have trouble in handling. Recently, higher performance and higher function are expected, and when a multi-channelization proceeds, a heating value at the tip portion of the ultrasonic probe becomes larger.
Therefore, there is a problem in that a sufficient heat radiation cannot be obtained only by heat radiating to a rear side of the ultrasonic probe with a heat conducting member. In order to improve the heat radiation, there has been proposed a configuration in which a cooling jacket is wound around the ultrasonic probe, and refrigerant is circulated in the cooling jacket, thereby coercively cooling the ultrasonic probe (see, e.g., JP-A-2005-027737).
In the cooling configuration disclosed in JP-A-2005-027737, a flexible circulation tube is used for circulating the refrigerant through the cooling jacket, and the circulation tube is clamped along a signal cable for transmission to and reception from the ultrasonic probe. In an application of an ultrasonic inspection device, good handling ability is required. However, since the circulation tube disclosed in JP-A-2005-027737 is provided separately from the signal cable, the handling ability is not good. In addition, even if the circulation tube and the signal cable are simply integrated in a composite manner, there are problems in that an insulation coating of the signal cable may be adversely affected by a dew condensation that is likely to be generated on an outer surface of the circulation tube through which the refrigerant flows, and in that bending property etc. need to be considered.